Study On Characteristics Of Stata Behavior In Mining Height Fully-Mechanized Face Of 6.2m In Yang Changwan Coal Mine

Technology about high cut in fully mechanization face is used to mine 5.5m thick coal seam in Yang Changwan Coal Mine where the coal seam thickness is 7.1m. To solve the problems of intensive strata behaviors and bad stability of rib spalling in working faces with great mining height, taking the working face with mining height of 6.2m in Yang Changwan Coal Mine as an engineering background, the strata behaviors and the mechanism of rib spalling are studied deeply and systemically in this paper, based on scene measure way, model simulation test in the laboratory, numerical analysis by computer and theory analysis.Using scene measure way to study the roof activity rule, it is indicated that the pressure step distance excursion is 27.4³5.8m, the weighting span is 35.4⁴8.6m, the cycle weighting strength is 20.1m; The support′s loads and the support′s maximum resistance is 4278kN, 7182kN, the characteristics of strata behavior in the large mining height fully-mechanized face are particular with these of other mining technology. It is especially included that the support load and coefficient of dynamic load are bigger during the periodic ground pressure than during the first weighing, that the weighting of main roof obviously occurs and the coefficient of dynamic load is littler, that the rules of abutment pressure ahead of face are obtained. The peak of abutment pressure is 8.2m. There are three type of wall depredation: half of wall depredation, wall depredation and whole wall depredation.Uing model simulation test in the laboratory, strata behaviors in large mining height fully-mechanized working face are obtained through model simulation test. It is indicated that the pressure step distance is 32.5m, the weighting span is 47.5m, the cycle weighting strength is 25m; The initial is about 7600kN, the maximum resistances is 11000kN. The result between scene measure way and model simulation test is liner.The motion law of the overlying strara and the law of the stress distribulation and the feature of the wall depredation during the weighting and the cycle weighting are researched by FLAC^3D. It is indicated that the result between model simulation test in the laboratory and FLAC^3D software is liner. The support′s resistance is 11136kN when the mining height is 6.2m. The result among scene measure way, model simulation test and numerical analysis is liner.The mechanism of the rib spalling is preliminarly studied by the suppressed shaft and the results are tested and verified by the measuring in-situ-results.There are two type of wall depredation: half of wall depredation and whole wall depredation.The 0.65 times of the wall is the easiest unstable position. Finaly, we get that the distinct coal strength has different depredation type.The results of study will enrich the theories on strata behavior law for large mining height fully-mechanized working face, and it provides some basis for mine under similar geological conditions.